HID: i2c-hid: define i2c_hid_read_register() and use it

Handling simple read of device registers in __i2c_hid_command() makes it
too complicated and the need of special handling for the HID descriptor
register adds even more complexity. Instead, let's create simple
i2c_hid_read_register() helper on base of i2c_hid_xfer() and use it.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index 856778d..32d275d 100644 (file)
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -104,14 +104,6 @@ struct i2c_hid_cmd {
        .opcode = opcode_, .length = 4, \
        .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
 
-/* fetch HID descriptor */
-static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
-/* fetch report descriptors */
-static const struct i2c_hid_cmd hid_report_descr_cmd = {
-               .registerIndex = offsetof(struct i2c_hid_desc,
-                       wReportDescRegister),
-               .opcode = 0x00,
-               .length = 2 };
 /* commands */
 static const struct i2c_hid_cmd hid_reset_cmd =                { I2C_HID_CMD(0x01) };
 static const struct i2c_hid_cmd hid_get_report_cmd =   { I2C_HID_CMD(0x02) };
@@ -243,6 +235,14 @@ static int i2c_hid_xfer(struct i2c_hid *ihid,
        return 0;
 }
 
+static int i2c_hid_read_register(struct i2c_hid *ihid, __le16 reg,
+                                void *buf, size_t len)
+{
+       *(__le16 *)ihid->cmdbuf = reg;
+
+       return i2c_hid_xfer(ihid, ihid->cmdbuf, sizeof(__le16), buf, len);
+}
+
 static size_t i2c_hid_encode_command(u8 *buf, u8 opcode,
                                     int report_type, int report_id)
 {
@@ -268,13 +268,8 @@ static int __i2c_hid_command(struct i2c_hid *ihid,
        int length = command->length;
        unsigned int registerIndex = command->registerIndex;
 
-       /* special case for hid_descr_cmd */
-       if (command == &hid_descr_cmd) {
-               *(__le16 *)ihid->cmdbuf = ihid->wHIDDescRegister;
-       } else {
-               ihid->cmdbuf[0] = ihid->hdesc_buffer[registerIndex];
-               ihid->cmdbuf[1] = ihid->hdesc_buffer[registerIndex + 1];
-       }
+       ihid->cmdbuf[0] = ihid->hdesc_buffer[registerIndex];
+       ihid->cmdbuf[1] = ihid->hdesc_buffer[registerIndex + 1];
 
        if (length > 2) {
                length = sizeof(__le16) + /* register */
@@ -794,8 +789,9 @@ static int i2c_hid_parse(struct hid_device *hid)
 
                i2c_hid_dbg(ihid, "asking HID report descriptor\n");
 
-               ret = i2c_hid_command(ihid, &hid_report_descr_cmd,
-                                     rdesc, rsize);
+               ret = i2c_hid_read_register(ihid,
+                                           ihid->hdesc.wReportDescRegister,
+                                           rdesc, rsize);
                if (ret) {
                        hid_err(hid, "reading report descriptor failed\n");
                        kfree(rdesc);
@@ -905,7 +901,7 @@ static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
        struct i2c_client *client = ihid->client;
        struct i2c_hid_desc *hdesc = &ihid->hdesc;
        unsigned int dsize;
-       int ret;
+       int error;
 
        /* i2c hid fetch using a fixed descriptor size (30 bytes) */
        if (i2c_hid_get_dmi_i2c_hid_desc_override(client->name)) {
@@ -914,11 +910,14 @@ static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
                        *i2c_hid_get_dmi_i2c_hid_desc_override(client->name);
        } else {
                i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
-               ret = i2c_hid_command(ihid, &hid_descr_cmd,
-                                     ihid->hdesc_buffer,
-                                     sizeof(struct i2c_hid_desc));
-               if (ret) {
-                       dev_err(&ihid->client->dev, "hid_descr_cmd failed\n");
+               error = i2c_hid_read_register(ihid,
+                                             ihid->wHIDDescRegister,
+                                             &ihid->hdesc,
+                                             sizeof(ihid->hdesc));
+               if (error) {
+                       dev_err(&ihid->client->dev,
+                               "failed to fetch HID descriptor: %d\n",
+                               error);
                        return -ENODEV;
                }
        }